In water circuits for heating or cooling, valves are used by means of which the flow rate through the water circuit is controlled, and therewith the amount of heat which is provided or withdrawn.
At heating arrangements having radiators, it is common that each radiator comprises its own valve arranged at its feeding connecting piece, which valve by means of a thermostatic control head, depending on the desired and the measured room temperature, starting from an opened position when the valve is not actuated more or less closes the feed pipe. For doing so, a closing spring arranged in the control head is more or less released by a driving element of the control head, e.g. a bimetal actuator or an expansion material element. In case for reaching or keeping, respectively, of the desired room temperature no addition of heat is required, the respective distribution valve is kept closed by the released closing spring of the control head.
At floor heating installations, the distribution of the heated heating water to the individual heating circuits typically is accomplished via a distribution manifold, which for each heating circuit has a branch line, by means of which the heating water is supplied to the respective heating circuit. In doing so, it is common to form by means of adjusting units screwed into the distribution manifold for each heating circuit an own distribution valve within the distribution manifold, by means of which distribution valve the flow rate through the branch line dedicated to this heating circuit is adjustable or controllable, respectively. In case of a controlling of the flow rate, this controlling is accomplished typically temperature controlled by means of an actuator which is arranged at the respective adjusting unit, which is activated by an external control unit and depending on the activation by the control unit more or less closes the distribution valve assigned to it. For doing so, a closing spring arranged in the actuator is more or less released by a driving element of the actuator, e.g. an expansion material element. In case no supply of heat to the respective heating circuit is required, the respective distribution valve is kept closed by the released closing spring of the actuator.
The control heads and actuators used today have the disadvantage that they are built from a large number of components, which renders them interference-prone, expensive in manufacturing and furthermore quite bulky.
The last mentioned disadvantage is especially annoying in particular in the last mentioned floor heating installations having distribution manifolds with a large number of distribution valves arranged side by side, since there is a permanent desire for a reduction in the space requirements of the distribution manifolds, which is opposed today essentially by the size (height and width) of the actuators.
A general disadvantage of today's radiator and distribution valves consists in that after an extended downtime of the heating installation, e.g. after the summer period, it often comes to malfunctions, because the valves, which then after a long time are released again by the closing spring of the control heads or actuators, respectively, often do not self-acting open again, thus no flow through the respective valve takes place and also no controlling via the control head or the actuator is possible.